<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>
	<body>
		
		<script type="text/javascript">
			let a = 3 , b = 4;
			
			
			alert( a-- == 3  ||   b-- ==3 ); // 是true 还是false？
			alert(a);  //
			alert(b); //
			
			// alert( a==3 && b==1  ) //false
			
			// alert(a == 3 || b == 1 )// true
			
			// alert (  !(a==3) )  //false
			
			
			
		</script>
	</body>
</html>
